Bulk-edge correspondence is a central concept of topological insulators. It states that topological indices defined independently for an infinite sample – the bulk – and for a half-infinite sample with boundary – the edge – actually coincide. Originally investigated in Quantum Hall effect [1]}, bulk-edge correspondence theorems have then been established for a wide range of models, both discrete [2]}, [3]}, [4]}, [5]}, [6]}, [7]} and continuous [8]}, [9]}, [10]}, [11]}, [12]}. Applications go beyond condensed matter physics, such as in optics [13]}, [14]}, acoustics [15]}, or fluid dynamics [16]}, actually to any wave phenomenon that can be described by a self-adjoint operator.
